The NexentaOS project has released the 2nd alpha of their OpenSolaris distribution, which uses the Debian userland and tools. It includes a new installer (with auto-partitioning), the addition of KDE, WiFi drivers, full support from booting off of removable drives such as USB sticks, the complete Mono platform including Beagle, Java runtime environment, OpenSolaris build 30, and much more. You can visit the getting started page (screenshots included), read the changelog, and then proceed to the downloads.

i've looked at opensolaris.org. developer's documentation of opensolaris is great. you've got there tutorials for making drivers, architecture of system. that is what, i think, makes this project very interesting to developers. opensolaris would have new hardware support very quick.